The present invention relates to magnetic recording, and more particularly to a method and system for providing a writer with improved performance due to the properties of the coil.
Inductive writers are typically used to write data to recording media. Inductive writers can be broken into two types based on how their zero-throat position is defined. The zero throat for an inductive writer is the position at which the first and second poles begin to diverge at the back edge of the write gap. For example, FIG. 1 depicts one conventional inductive writer 10 with a pedestal defined zero throat. The conventional writer 10 is typically part of a merged head that includes both a reader (not shown) and the conventional writer 10. The conventional writer 10 includes a first pole 12 having a pedestal 14, a first insulator 16, a coil 18, a second insulator 20, a second pole 22 and a write gap 24 defined by the insulator-filled space between the first pole 12 and the second pole 22. The first pole 12 and the second pole 22 are coupled through layer 21. Although the coil 18 is shown as having six turns, typically the coil has another number of turns. As can be seen in FIG. 1, the pedestal 14 diverges from the front of the second pole 22 at the position marked by the arrow 23. At this position, a portion of the first insulator 16 is flush with the pedestal 14. Also at this point, the pedestal 14 draws away from the second pole 22. Thus, the zero throat is defined by the pedestal 14. The coil 18 typically has a pitch of approximately, 1.5 micros, with the narrowest width of the turns as 1.1-1.2 microns with a turn separation of 0.3-0.4 microns. When a current is driven through the coil 18, magnetic field is concentrated at the write gap 24 by the poles 12 and 22. The edge of the writer 10 near the write gap 24 is at the air-bearing surface (xe2x80x9cABSxe2x80x9d), in proximity to the media. Thus, the conventional writer 10 can write to the media.
FIGS. 2A and 2B depict conventional writers 10xe2x80x2 and 10xe2x80x3, respectively, in which the zero throat position is defined by the second insulator 20xe2x80x2 and 20xe2x80x3, respectively. Portions of the conventional writers 10xe2x80x2 and 10xe2x80x3 are analogous to portions of the conventional writer 10 depicted in FIG. 1. Consequently, portions of the conventional writers 10xe2x80x2 and 10xe2x80x3 are labeled similarly. For example, the conventional writers 10xe2x80x2 and 10xe2x80x3 include a first pole 12xe2x80x2 and 12xe2x80x3, respectively. As can be seen in FIG. 2A, the second pole 22xe2x80x2 separates from the first pole 12xe2x80x2 due to the second insulator 20xe2x80x2 at the position marked by the arrow 23xe2x80x2. Similarly, in FIG. 2B, the second pole 22xe2x80x3 separates from the first pole 12xe2x80x3 due to the second insulator 20xe2x80x3 at the position marked by the arrow 23xe2x80x3. Thus, the conventional writer 10xe2x80x2 and 10xe2x80x3 define the zero throat position using the second insulator. The conventional writers 10xe2x80x2 and 10xe2x80x3 function in the same manner as the conventional writer 10. The conventional writer 10xe2x80x3 differs from the conventional writer 10xe2x80x2 in that the coil 18xe2x80x3 is sinked, residing on a depression in the first insulator 16xe2x80x3.
FIG. 3A depicts a flow-chart of a conventional method 50 for providing the conventional writers 10 and 10xe2x80x2. The first pole is provided, via step 52. The first insulator and pedestal are provided, via steps 54 and 56, respectively. The first insulator and pedestal are then planarized, via step 58. The write gap layer is then provided, via step 60. The coil is provided, via steps 62 through 66. A layer of photoresist is provided on the write gap, via step 62. The photoresist is then patterned to provide a mask, via step 64. The apertures in the mask are over locations on the first insulator where the coil will be plated. Thus, portions of the mask remaining indicate the spaces between the turns of the coil. The coil is then deposited, via step 66. Typically, the coil is plated in step 66. The coil typically has a pitch of no less than 1.5 microns, with spaces between the turns of the coil accounting for approximately 0.3-0.4 of the pitch. The second insulator and second pole are then provided, via steps 68 and 70, respectively. Depending upon whether the writer is a conventional pedestal defined zero throat writer 10 or a conventional second insulator defined zero throat writer, the second insulator may diverge from the write gap differently.
FIG. 3B depicts a conventional method 80 for providing the writer 10xe2x80x3 in which the coil 18xe2x80x3 is sinked. The first pole is provided, via step 82. The first insulator is provided, via step 84. The first insulator provided in step 84 is very thin, allowing the coil to be provided for the writer to be sinked such that the bottom of the coil is lower than the top of the pedestal, as in the writer 10xe2x80x3. The pedestal is then provided, via step 86. The pedestal is built up in step 86 such that the top of the pedestal is higher than the top of the first insulator. The write gap layer is then provided, via step 88. The coil is provided, via steps 90 through 94. A layer of photoresist is provided on the write gap, via step 90. The photoresist is then patterned to provide a mask, via step 92. The apertures in the mask are over locations on the first insulator where the coil will be plated. Thus, portions of the mask remaining indicate the spaces between the turns of the coil. The coil is then deposited, via step 94. Typically, the coil is plated in step 94. The coil typically has a pitch of no less than 1.5 microns, with spaces between the turns of the coil accounting for approximately 0.3-0.4 of the pitch. The second insulator and second pole are then provided, via steps 96 and 98, respectively. Depending upon whether the writer is a conventional pedestal defined zero throat writer 10 or a conventional second insulator defined zero throat writer, the second insulator may diverge from the write gap differently.
Although the conventional writers 10, 10xe2x80x2 and 10xe2x80x3 function, one of ordinary skill in the art will readily realize that there are several drawbacks to the conventional writers 10, 10xe2x80x2 and 10xe2x80x3. The second insulator defined zero throat writers 10xe2x80x2 and 10xe2x80x3 have poorer overwrite performance than the conventional pedestal defined zero throat writer 10. Thus, it is more difficult to overwrite data using the conventional writers 10xe2x80x2 and 10xe2x80x3 than the conventional writer 10. This is particularly true for low currents driven in the coil 18, 18xe2x80x2 and 18xe2x80x2. In addition, the writer 10 has a better controlled track width than the conventional writers 10xe2x80x2 and 10xe2x80x3 because the second insulator 20, which has a significant topography, is located farther from the edge of the conventional writer 10 that will be at the ABS. Thus, for many applications, the conventional writer 10 is preferred over the conventional writers 10xe2x80x2 and 10xe2x80x3.
However, one of ordinary skill in the art will readily realize that there are also drawbacks to the conventional writer 10. The conventional writer 10 has an apex angle. The apex angle is the angle the second pole 22 makes at the zero throat. This apex angle must be accounted for when placing the coil 18 in the writer 10. The front turn of the coil 18 must be placed far enough away from the zero throat, and thus from the ABS, to ensure that the coil 18 is insulated from the second pole 22. This also ensures that the track width can be controlled for the second pole 22. Placing the coil 18 farther from the ABS reduces the efficiency of the combination of the coil 18 and poles 12 and 22 in providing a high magnetic field near the write gap at the ABS. Thus, the efficiency of the conventional writer 10 is reduced.
One of ordinary skill in the art will also readily realize that the conventional writers 10, 10xe2x80x2 and 10xe2x80x3 have a relatively long yoke. The yoke is the length of the first poles 12, 12xe2x80x2, and 12xe2x80x3 and the second poles 22, 22xe2x80x2 and 22xe2x80x3 from the ABS. The yoke is long because of the coil 18, 18xe2x80x2 and 18xe2x80x3. The coil 18, 18xe2x80x2 and 18xe2x80x3 is desired to have a certain number of turns to generate sufficient magnetic flux for writing data using the writer 10, 10xe2x80x2 and 10xe2x80x3, respectively. In addition, the pitch of the coil 18, 18xe2x80x2 and 18xe2x80x3 is at least 1.5 microns or longer. The coils 18, 18xe2x80x2 and 18xe2x80x3 often are fabricated in situations where there is significant topography in the region of the coils 18, 18xe2x80x2 and 18xe2x80x3, Thus, reducing the pitch of the coil or fabricating a double layer of coils using the conventional photolithographic techniques described in FIG. 1 is difficult. Thus, the yoke of the poles 12, 12xe2x80x2 and 12xe2x80x3 and 22, 22xe2x80x2 and 22xe2x80x2 remains relatively long. A longer yoke has a lower writing efficiency. In addition, the coil 18, 18xe2x80x2 or 18xe2x80x3 may be longer and have a higher inductance. As a result, the coil 18, 18xe2x80x2 and 18xe2x80x3 has a lower switching speed. Consequently, the speed of the conventional writers 10, 10xe2x80x2 and 10xe2x80x3 is lower. In addition, a longer yoke reduces the efficiency of the writer 10, 10xe2x80x2 and 10xe2x80x3. Thus, the conventional writers 10, 10xe2x80x2 and 10xe2x80x3 have reduced speed and efficiency.
Accordingly, what is needed is a system and method for providing a writer with improved efficiency and performance. The present invention addresses such a need.
The present invention provides a method and system for providing a writer. The method and system comprise providing a first pole, an insulator covering a portion of the first pole and a coil on the first insulator. The coil includes a plurality of turns. The method and system also comprise providing a second insulator covering the coil, providing a second pole on the second insulator and providing a write gap separating a portion of the first pole from a second portion of the second pole. A first portion of the second pole is coupled with the first pole. In one aspect, the method and system include providing a coil having a plurality of turns with a pitch of no more than 1.2 micrometers. In another aspect, the plurality of turns of the coil is provided using a hard mask layer on a photoresist layer. A portion of the hard mask layer and a portion of the photoresist layer define a plurality of spaces between the plurality of turns of the coil. In another aspect, the writer is a pedestal defined zero throat writer. In this aspect, the first insulator has a depression therein and the coil is provided on the depression.
According to the system and method disclosed herein, the present invention provides a writer which can have a shorter yoke due to narrower pitched coils as well as coils that are placed closer to the write gap, thereby increasing the speed and efficiency of the writer.